Radio receiving set



H. D, @URRHER RADIO RECEIVING SET Nov. 22, 1927.,

3 Sheets-Shes?, l

Filed Sept. 8, i925 H. D. CURRIER RADIO RECEIVING SET Sheets-Sheet 2zuren Haml'zzrn'en Nov. 22, 1927.

H., n, CURRHER RADIO RECEIVING SET Filed Sept, 8. i923 3 Sheets-Skaai 3,Patented Non. 22, 192?.

HIB/ABI D. CTRRIER, OF CHICAGO, ILLINOIS, ASSIGNOR TO 'KELLOGGSWITCHBOARD AND SUEPLY COI/IPAIIY, OF CHICAGO, ILLINOIS, A CORPORATIONOF ILLINOIS.

RADIO RECEIVING- SET.

Application led September 8, 1923.

My invention relates to the art ot wireless or radio, and has to do moreparticularly with the apparatus and circuits used in systems ot radio orwireless.

In the transmission ot radio n'iessages a Yery high frequency current isused to carry the radio signals, and the sets that are to receive thesignals irom the transmitting station mustbe constructed to function inresponse to these extremely high oscillations. rihe high frequencycurrents are generally picked up by an antennal or loop and carried to atuning coil in the receiving set. rIhe tuning coil generally consists ora number of turns of wire wound upon a tube of insulating material or a.min'iber of turns ot wire wound upon a molded member' of insulatingmaterial. It has been found that .large losses occur due to leakage anddrainage ot the coils owing to the fact that the convolutions of wireare in contact with the supporting tube or form. It is one of theobjects of my invention to construct a` coil which obviates a .largepercentage of this loss found in the coils of the prior art. This lossmay be overcome to a large extent by lessening the Contact spacel ot thewinding or windings ot the coil with the supporting member or frame insuch a manner that a very small percentage of the winding actuallycontacts with the supporting member or members.

It is a further object of my invention to so arrange the circuits andapparatus as to greatly increase the e'liiciency ot the same thereby notonly obtaining a greater volume or strength ot signal, but at the sametime vastly increasing the selectivity and sensitivity ot the circuitsand apparatus.

A still further feature ot my invention resides in the novel circuitarrangement which I use in transmitting the plate variations caused bythe incoming signals back to the grid circuit to sustain the incomingoscillations.

The features just mentioned, as well as others, relating to the 'detailof construction, combination. of parts, and circuit arrange- Scrial No.661,552.

ment will be hereinafter more particularly pointed out in the ensuingspecification and appendedl claims.

F or a more complete understanding of my invention, reference may be hadto the accompanying sheets of drawings in which like referencecharacters, in the different views, denote like parts, and in which;

Fig. 1 is a rear elevation of one of my combined tuning and feed backcoils or coupler;

Fig. 2 is a side elevation ot the same;

3 shows a second `form of my combined antenna and feed back coil orcoupler. rIbis is a front View ot` the same;

Fig. 4: is a side View of the coil shown in Fig. 3; and

Fig. 5 is a. diagrammatical illustration ot the circuit ot a, receivingset using my type ot coil and feed back circuit.

Referring now more particularly to Figs. 1 and 2. it will be noted thatthe coils and means for varying the same are mounted upon a sub-panel orplate 2, and constitute a unitary structure. The device, as a whole, isadapted to be secured to a panel 3 by means ot screws 4, which extendthrough spacing lugs 5 for properly spacing` the mounting plate from thepanel 3. Attached to the plate 2 is a pair of arms G and 7 which supportthe frame upon which the windings are wound. rlhese arms are secured tothe plate 2 by screws 8. The winding trame consists ot two plates 9 and10 ot insulating material which are dove-tailed into each other to :termfour arms. rlhe arms 11 and 12 er: tend at right angles to the arms 13and 14. A. portion of each of the arms is cut away, as shown at 15 and1G forming an edge 17, which is chamtered ott to torni a Very narrowcontacting space 'for the wire which forms the inner or secondarywinding 18. The winding 18 is wound upon these arms and equally spacedto form a continuous secondary or feed back winding. Strips 2O areplaced between the projecting ears 21 and 22 of the arms 11, 12, 13 and14 and are secured in position by means of of the prior coils which weredircctl screws The outer edges ol these strips are ehaintered ott), asshown. most clearly at 24 in Figure 9. The primary Winding consists ofWire Wound upon these strips and equally spaced. The turns of thesecondary Winding are connected to electrical terminals 25 and 26 andtheterminals o't the primary Winding are connected to electricaterminals 27 and 2S. The trame Work and coils are held in position withreference to the arms G and 7 by means ot screws 2). At the point Wherethe prin'iary Windingr con tacts with the cham'tere'd edge ol strip Q()carried by arin 1Q, the insulation (it insulated Wire is used) isremoved7 so thatI a slidable Wiper 3l may make electrical contact witheach convolution or turn of the primary Winding.

Extending` through the panel plate 3 and mounting` plate 2 .is a shaft32, to the end et which is connected a gear Wheel 83 by means ot a screwEll, and to the outer end opt the shalt 32 is connected a dial orcontrollingl member (not shown) for rotating' the gear 33. Attached tothe plate 2 is a track meinber 35 and litting into this track member isa rack 36 which has teeth thatv mesh with the teeth ot the gear 33.AttachedL to the rack member 36 is a Wiper 3l which is adapted toContact with the portion oit the primary Winding immediately above thechamfered edge ot strip 2O ot arm l2. il preefnire spring 37 riveted tothe W'pcr 3l and has contact with track to insure good electricalconnection between the Wiper and the track 35. A terminal 38 isprovided, which is connected to the Wiper through track and rack 3G.rlhe turning ot the dial whicl.. rotates the shaft 32 causes the Wiperto move across lthe primary Winding* trame from one end thereol' to theother end thereol".

From the foregoing` it will be noted that the primary Winding: andsecondary winding are each rectangular interni and only cngag'e thesupporting traine at tour points ot contact. By this method oitconstructiom l get away trom the hirge leakage or drainage in Contactwith the supportinge` tube or niember throughout the ci Ire lengththerco'i.

It may also be pointed out that by this method oit constructionv1 l amable to inaliecontact and engage with each ctnivolution or turn of the.primary Winding` thereby torniing' an accurate means ot adjustment ot'the primary Winding.

Referring to Figs. and et, l here show dillerent form ot coupler whichconsists ol a primary WindingV 50, and a seeomlary wind- The primaryWinding is provided ing 5l. with taps which extend to contact buttonsjwhich buttons are for engagement( With a Wiper 59 so that the effectiveturns ot the primary Winding may be adjusted by means of the wiper. Thecoils and adjustable switch are connected to a sub-base 52 which isadapted to be secured to a panel 53 by means ot screws 54. Spacinglugsare provided to accurately .space the sub-panel or plate 52 relative tothe panel 53. rlfhe secondary Winding 5l is 'toi-ined by Windingsuitable insulated Wire upon a cylindrical form and then ccinentingg theai'ljaccnt turns together to form a single winding'. A. groove 5S cut inthe plate and the scc-- ondary winding' cemented into this groove., sothat it only contacts with the plate 52 Where it extends into the groeveSti. The primary windingl is of the same :torni and is made by Winding'suitable insulated wire up- On a cylindrical lormr` then cementing theturns togetherl and removingr the same from the form. The coil is theninserted in a circular groove 5T in plate The primary Winding isprovided with a number ot' taps 5S. kRotatably secured to the plate 52is a wiper 59 which is 'fastened to a sha'tt SO that extends through thepanel 5?) and is provided at its outer end with a, dial or controllin;lmember. Arranged in a circle on plate 52 are a number ot" contactbuttons (3l, which are provided with extension terminals (3&2.Qonductors 63 are connected to the taps 5&5 of Coil 5() and extendthrough orii'iccs in the plate 52 to the terminals 62. The wiper 59 isacapted to rotate to make Contact vith the contact butto-ns (il, wherebythe primary coil may be tapped at any desired point. llerminals G5, (lt,G7 and G8 are 'fastened to the plate 52 and have conductors extendine`to the primary and secondary windings E() and 5l., From this descriptionit will be that the primary Winding; and secondary Windingare each aself sujfpoitingv winding'l and onlj.1 Contact with the supporting'plate onel end there/ol.

Referring' now more particularly to Fin4 ure 5./ l here show the primaryWindiurj ot either ot' my coils connected through a variable tuning);condenser to an antenna 7l. The arroiv T). may either bc the Ywiper 3lof Figures l and or the Wiper 5) (it Figures and #la and is ada ted toadjust the antenna inductance ot the primary winding4 oil either ol mycoils.

l'letcrencc characters 75" T6 and TT reprer4 sent audion or facuuintubes. beine' the detector audion and 7G and 7T beine' the :unpli'tyinggaudions. The reference characters AT and AT rej'nescnt audio lrcoucncvtranstormers. the primary windingl ot transformer AT connected to theplate ot the detector tube aud to the positivo terminal ot B battery 78,and the secoiidary ivindinc of this transformer is connected to the gridot tube 76 and to ground 80 and to the negative terminal ot A battery3l. The primary Winding;` of transformer AT is connected to the plate ottube 76 and to the positive terminal of B battery 82 and the secondaryCil winding of this transformer is connected to the grid of tube 77 andto the negative terminal of A batt ery 3l. The plate ot tube (7 isconnected through the receivers R, or through a loud speaker to thepositive terminal ot B battery 82. The usual rheostats lil, R2 and R3are provided 'tor controlling the filament current of the filaments oftubes 75, 76 and 77 respectively.

The grid et the detector tube 75 extends through the usual gridcondenser S3, with its associated grid leal: to a point Vbetween oneterminal ot the primary winding` and the tuningr,Y condenser 70. Theother terminal o'l the priniary winding,` may be lett open or connectedby conductor SG to ground, in which instance, when the arrow is adjustedit controls the short-circnited turns ot the primary winding. l haveAfound it desirable in some instances to ground. the unused turns ol theprimary winding'. A conductor extends Atrom the plate olf the detectortube l5 through a variable condenser S7 and a secondary winding` o't thecoupler or tuningcoil back to the negative iilamentterminal ot thedetector tube. lt will be noted that the secondary coil or leed backcoil is connected between the plate of the detector tube and negativelilament terminal ont the detector tube.

To tune in the oscillations ot a transn'iittine' station, the antenna istuned to the wave of the transmitting,` station by means ot the arrow 72and the variable condenser TO. rlhe incoming signals, whentuningproperly made are eii'cctive upon the `grid ot tubo 75, to varythe electron i'iow between plate and `filament ot the detector tube, inthe usual manner, and the plate potential variations are brought back tothe grid by the secondary winding oit the coil, which serves to impressthese variations upon the grid ot the detector tube 75 inductively,through the windings of the coil. The variable condenser S7 assists incontrolling the 'feed baclr through the secondary windingV and it willbe noted that the feed baclr through this winding;- is oit radiofrequency, and that it doesA not pass tlirough a high impedance coil asin other circuits. The audio frequency trausiiorn'iers AT and AT withtheir associated audions amplify the incoining signals in the usualmanner.

l have liound that by extending,` the plate circuit through a 'variablecondenser Si' and the feed back winding,` ot the coil, that l' am ableto greatly increase tl e strength ot the incoming signals, over theolder method of placing` the feed bacl winding in series with theprimary winding` of the transformer AT, in which instance the `t'eedback winding receives audio frequency happenings instead oit radiofrequency happenings, as in the present case. l also find that theselectivity and the sensitivity oit the circuit arrangement is greatlyincreased by my eethod ot ieed back.

From the above it will be noted that my tuning coils are of a verysimple construction and are supported by only a very small percentageoit their area, thereby doin away with leakage from the coil to thesupporting surface. The variable condenser and rheostat R permit anaccurate control of the radio frequency 'feed back to the secondary otlthe coil.

Vilhile I have described two particular 'terms ot coils and a particularcircuit arrangenient, it is to be understood. that changes andinodilications will readilv suf;- geit themseh'es to those skilled intile art, and l, theroliore, do not wish to be limited to the exactstructure and circuit arrange-A ment, as shown, but aim to cover allsuch changes and modifications, as come within the spirit and scope otthe appended claims.

lll/'hat l claim as ne and desire to secure by United States Letterslgatent, is:

l. A coil olf thevcharacter described including a plurality ot armspofio `ed at right angles relative to cach other supporting aI spacedprimary winding' comprising turns ot wire ot substantially the samelength, and members attached to said arms supporting a spaced secondwinding.

2. A device ot the character descr cluding a supporting tramecouiprisaip; a plurality o't arms positioned in angular-'relation toeach other, a windingspaced on said trame, menibers attached to saidarnit-t, a .second spaced. winding supported by said members. and aslidable, n'iember tor making;- electrical contact with dil'lercnt turnsoi one of said windings of said device.

3. A device of the character described including' a supporting tramecomprising),v a plurality ot arms positioned in angular relation to eachother, a` winding spaced on said trame, meml'iers attached to saidarms.y a second spaced wii'idingf,` supported by said members, aslidable member Ytor making' electrical contact with dill'erent turns otone of said windings, and a rotatable member 'lor movingv said slidablemember back and lorth across said windin' al. A device oit the lharacterdescribed including` a mountinfpg plate, a simportiner trame comprisingva pluralirfv ol arms positioned at right angles relative to each otherattach-ed to said mounting' plate by supporting arms, a pair otlongitudinally extending spa ed windings supported by said tramo, and acontact member support-ed by said plate for making electrical contactwith one of said windings.

5. A device of the character described including,` a mounting plate, asupporting .trame comprisingl a. plurality ot arms positioned at rightangles relative to each other attached to said mounting plate bysnpporting members connecting said arms to said plate, a pair of spacedwindings supported by said trame, a contact member supported by saidplate for making electrical Contact with one ot said windings, and arotatable member journaled in said supporting plate iter moving saidcontact member back and forth across said winding.

6. A device of the character described including arms positioned inintersecting planes supporting an angularly shaped primary windinghaving turns oi' substantially the same length and an angularly shapedsecondary winding, the one winding being within the other and ininductive relation thereto.

7. A device ot the character described in* eluding a trame having aplurality ot arn'is positioned in intersecting planes and supporting` aspaced winding having turns of substantially the same length, andmembers adapted to be attached to the said arms ot said :trame forsupporting a second spaced winding having` turns ot substantially thesame length7 said second winding` being in inductive relation to saidiirst winding.

8. A device et the character described including` a trame having aplurality of arms positioned in intersecting planes and supporting` aspaced winding, nembers adapted to be attached to the said arms of saidtrame supporting a second spaced winding having turns of substantiallythe sain-c length, said second winding being in inductive relation tosaid first winding, and a contact member adapted to be adjusted Yforelectrical connection with diilierent turns oi one ot said windings.

9. A device ot the character described including a frame having` aplurality ci arms positioned in intersecting planes and supporting aspaced winding, members adapted to be attached to the said arms oit said'iframe supporting a. second spaced winding, and a slidable memberadapted to slide back and forth across one of said windings to makeelectrical contact with different turns ot' said windings.

l0. A device of the character described including a trame having aplurality o'l arms positioned in intersectingplanes and supporting a.spaced winding, members ada pted to be attached to the said arms oi?said trame supporting a second spaced winding, a slidable member adaptedto slide back and forth across one ot said windings to make electricalContact with different turns of one of said windings, and a rotatablemember Yor controlling said slidable member.

l1. A device ot the character described having a mounting `amecomprising rela tively thin arms positioned in iirlersecting planes andadapted to receive a plurality of' spaced turns ot wire to iorinwiniling, and a plurality ott thin strips adapted to be secured to saidarms to support a second spaced winding in inductive relation to said:first winding.

12. A device ot the character described having a mounting framecompri-sing relatively thin arms positioned in intersecting planes andadapted to receive a plurality oi turns of wire ot' substantially thesame length to form a spaced winding, a plurality oil thin stripsadapted to be secured to said arms to support a second spaced windinghaving turns ot substantially the same length, and a contact member torinaliing eleetricl engagement with diierent turns ot one of saidwindings.

A device oi' the character described cluding a support-ing :trame hav ifa i, rality o'lf arms positioned in angular rele tion to each other, aspaced winding sur ported by said arms, and a slidable member adapted tonr ce eiectrical en," p a t t the turns oit said winding .in'nnediz'd'elI at jacent the point where theturne` contact wit one ci said arms.

14:. A device ot the character described comprising a plurality otariAAV positieT l in angular relation to each other, a spaced windingsupported by said arms, strips sccured to said arms, a second spacedwii'uling supported by said strips, and a contact member adapted to makecontact with diiilerent turns of one of said windings immediatelyadjacent the point where one ot said windings is supported by one oitsaid strips,

15. A device ot the character described including an angular trame workcomprising a plurality of intersecting arms supportiniean angularlyshaped spaced winding. a contact member adapted to make electrical engagement with different turns ol2 said winding in'nnediatelj-,f aiacetthe point where the winding contacts with saidA trame. and a secondangularly shaped spaced winding supported by the arms ot said traine.said second winding being within the other winding. Y

Signed by me at Chicago in the eounlv ot Cool; and State of Illinois,this 5th dal-,rr ot September, 1923. A

nini/iM n. cuni-nan.

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